LAKE BUENA VISTA, Fla. — In about one week, Mets manager Terry Collins said, his team will begin to assign roles for his relief corps.

Heading into the final days of spring training, one spot in the Mets' bullpen remains theoretically open. But one of the leading candidates, D.J. Carrasco, has been sidelined long enough to limit his viability in the competition.

Carrasco twisted his right ankle last week. Though he has thrown multiple bullpen sessions, he harbors concerns about the ability to field his position. Back in Port St. Lucie today, Carrasco told MLB.com “it’s not looking” like he’ll be healthy for Opening Day.

Meanwhile, here at Disney’s Wide World of Sports, pitching coach Dan Warthen said he hoped Carrasco could appear in a minor-league game Sunday.

Collins said he was not aware of Carrasco’s assessment of his ankle.

The spot appears to belong, then, to 41-year-old veteran Miguel Batista, who allowed a homer, and four runs total, in today’s 9-4 loss to the Atlanta Braves.

Batista figures to be the favorite, aided by his experience and his ability to start in emergencies.

Collins mentioned Chris Schwinden or another left-hander (like Daniel Herrera) as an outside contender. Collins is reticent to publicly assign roles at this time of year — he balked today at officially declaring Josh Thole his starting catcher.

But with Batista in the driver’s seat, what, then, of Carrasco? The team cannot make a decision on what to do until his health clears up.

A trade is one option, although Carrasco’s salary ($1.2 million) and 2011 results (6.02 ERA) limit his value. The Mets would likely have to absorb some of his contract to make a deal.

If they opt to send him to Triple-A Buffalo, Carrasco would first have to accept the assignment and then clear waivers.

But a stint on the disabled list buys the club time. This way, they guarantee control of Carrasco, who could rejoin the team if Batista proves ineffective or if Mike Pelfrey’s own sprained ankle forces Batista into the rotation.

• With center fielder Andres Torres (strained calf) still out of action, talented defender Matt den Dekker transferred back to big-league camp. Collins called him “a legitimate consideration” to make the major-league club, but that would be quite a leap.

Den Dekker, 24, has played just 72 games above Class-A, and it’s more likely the team would prefer that he receive minor-league seasoning rather than fill a big-league bench role. The same logic applies to outfielder Kirk Nieuwenhuis.

• Johan Santana completed a successful bullpen session, two days after his 69-pitch outing against St. Louis. Santana struck out six in his six innings of work that day.